BSplineInterpolateVectorImageFunction< TImage, TInterpolator > Class Template Reference

#include <itkBSplineInterpolateVectorImageFunction.h>

Detailed Description

template<typename TImage, typename TInterpolator>
class BSplineInterpolateVectorImageFunction< TImage, TInterpolator >

Helper class to interpolate each component of a VectorImage using separate B-Spline interpolators.

This class enables feature-wise interpolation of ITK VectorImages using one B-Spline interpolator per channel. It supports evaluation at arbitrary physical points and returns the interpolated values or spatial derivatives as Torch tensors for downstream use in workflows.

Author

V. Boussot, Univ. Rennes, INSERM, LTSI- UMR 1099, F-35000 Rennes, France

Note

This work was funded by the French National Research Agency as part of the VATSop project (ANR-20-CE19-0015).

If you use the Impact anywhere we would appreciate if you cite the following article:
V. Boussot et al., IMPACT: A Generic Semantic Loss for Multimodal Medical Image Registration, arXiv preprint arXiv:2503.24121 (2025). https://doi.org/10.48550/arXiv.2503.24121

Definition at line 43 of file itkBSplineInterpolateVectorImageFunction.h.

Public Types
using	ImageType = TImage
using	InterpolatorType = TInterpolator

Public Member Functions
	BSplineInterpolateVectorImageFunction ()=default
torch::Tensor	Evaluate (typename ImageType::PointType point, std::vector< unsigned int > subsetOfFeatures) const
torch::Tensor	EvaluateDerivative (typename ImageType::PointType point, std::vector< unsigned int > subsetOfFeatures) const
void	SetInputImage (typename ImageType::Pointer vectorImage)

Private Attributes
std::vector< typename InterpolatorType::Pointer >	m_Interpolators

Member Typedef Documentation

ImageType

template<typename TImage, typename TInterpolator>

using BSplineInterpolateVectorImageFunction< TImage, TInterpolator >::ImageType = TImage

Definition at line 46 of file itkBSplineInterpolateVectorImageFunction.h.

InterpolatorType

template<typename TImage, typename TInterpolator>

using BSplineInterpolateVectorImageFunction< TImage, TInterpolator >::InterpolatorType = TInterpolator

Definition at line 47 of file itkBSplineInterpolateVectorImageFunction.h.

Constructor & Destructor Documentation

BSplineInterpolateVectorImageFunction()

template<typename TImage, typename TInterpolator>

BSplineInterpolateVectorImageFunction< TImage, TInterpolator >::BSplineInterpolateVectorImageFunction ( )

default

Member Function Documentation

Evaluate()

template<typename TImage, typename TInterpolator>

torch::Tensor BSplineInterpolateVectorImageFunction< TImage, TInterpolator >::Evaluate	(	typename ImageType::PointType	point,
		std::vector< unsigned int >	subsetOfFeatures ) const

Interpolates the selected feature channels at a given physical point.

Parameters

point	The physical coordinate where interpolation is performed.
subsetOfFeatures	Indices of feature channels to interpolate.

Returns

A 1D torch::Tensor containing interpolated values for the requested channels.

EvaluateDerivative()

template<typename TImage, typename TInterpolator>

torch::Tensor BSplineInterpolateVectorImageFunction< TImage, TInterpolator >::EvaluateDerivative	(	typename ImageType::PointType	point,
		std::vector< unsigned int >	subsetOfFeatures ) const

Evaluates the spatial derivative of selected features at a given point.

Computes gradients of the selected feature channels with respect to spatial dimensions using the underlying B-Spline interpolators.

Parameters

point	The physical coordinate at which derivatives are computed.
subsetOfFeatures	Indices of feature channels to differentiate.

Returns

A 2D torch::Tensor (Channels × SpatialDimension) with spatial gradients per feature.

SetInputImage()

template<typename TImage, typename TInterpolator>

void BSplineInterpolateVectorImageFunction< TImage, TInterpolator >::SetInputImage

(

typename ImageType::Pointer

vectorImage

)

Initializes one B-Spline interpolator per feature channel in the input VectorImage.

Each channel of the vector image is assigned a separate B-Spline interpolator, as ITK's BSplineInterpolateImageFunction does not natively support VectorImages.

Parameters

vectorImage

The input VectorImage to initialize the B-Spline interpolators for each channel.

Member Data Documentation

m_Interpolators

template<typename TImage, typename TInterpolator>

std::vector<typename InterpolatorType::Pointer> BSplineInterpolateVectorImageFunction< TImage, TInterpolator >::m_Interpolators

private

Definition at line 89 of file itkBSplineInterpolateVectorImageFunction.h.